Biomechanical comparison of conventional open reduction and internal fixation versus calcium phosphate cement fixation of a central depressed tibial plateau fracture

Objective: To evaluate the effect of calcium phosphate bone cement on stability and strength of the fracture repair in a central depressed tibial plateau fracture cadaveric model. Design: Paired human cadaveric tibial specimens. Setting: Biomechanics laboratory. Patients: Uniform pure depression fractures of lateral tibial plateau were created in twenty human cadaveric tibial specimens. Intervention: The first part of the study used thirteen pairs of tibiae in two groups: a control group receiving the conventional treatment of morselized bone graft and two cancellous screws and an experimental group receiving calcium phosphate bone cement only. The second part of the study used seven pairs of tibiae in two experimental groups: one receiving calcium phosphate bone cement with a more extensive void preparation and the other group receiving calcium phosphate bone cement with a more extensive void preparation and two screws. Main Outcome Measurements: Each tibia was loaded on a Material Testing Systems machine from twenty newtons to 250 newtons for 10,000 cycles to simulate immediate postoperative load transmission to the tibial plateau. Specimens were then loaded to failure to determine the ultimate strength of the re construction. Displacement of the articular fragment and stiffness at each cycle were measured during dynamic loading. Peak load, deformation at peak load, and resistance to depression were measured during the load to failure. Results: The treatment of depressed tibia plateau fractures with a calcium phosphate cement provides equivalent or better stability than conventional open reduction and internal fixation in pure depression tibial plateau fractures. If the fracture void is prepared by eliminating the cancellous bone under the subchondral plate, the results are further improved. Conclusions: This study suggests that the non-weight-bearing postoperative period may be significantly reduced without clinically significant articular collapse.